A known vehicle drive system is configured to input rotations of an engine via a clutch to a transmission to allow the transmission to convert the rotations inputted to the transmission; therefore, the rotations converted by the transmission is outputted therefrom to drive a vehicle. Generally, a multiple-speed transmission having two parallel shafts is applied as the transmission of the known vehicle drive system. The two parallel shafts of the multiple-speed transmission correspond to input and output shafts. Multiple drive gears having a different number of gear teeth from one another are axially arranged at the input shaft of the multiple-speed transmission. Multiple driven gears engaging with the drive gears, respectively, are axially arranged at the output shaft of the multiple-speed transmission. Thus, the multiple-speed transmission having the two parallel shafts is configured to establish multiple gear stages by the selection of the drive gear and the driven gear. In those circumstances, for example, in a case where the transmission having the two parallel shafts is applied alone in the vehicle drive system and the number of gear stages to be established is increased, the number of drive gears and driven gears axially arranged at the parallel shafts increases, thus increasing an axial length of a housing of the transmission. For example, in a known vehicle drive system disclosed in WO2007/011212A (which will be hereinafter referred to as Reference 1), in order to restrain an increase of an axial length of a housing of a transmission (a gearbox) having two parallel shafts, a single planetary gear is arranged between a clutch and the transmission. Consequently, according to the vehicle drive system of Reference 1, a multiple-speed transmission establishing a multiple number of gear stages by use of the planetary gear arranged between the clutch and the transmission, and reducing the axial length of the housing is attained.
However, according to the vehicle drive system disclosed in Reference 1, a dry brake is included in a ring gear of the planetary gear; therefore, the vehicle drive system has a complex configuration. In addition, costs of the vehicle drive system and the weight of the vehicle drive system may increase. Moreover, energy loss due to a brake drag may be caused.
A need thus exists for a vehicle drive system which is not susceptible to the drawbacks mentioned above.